1. Field of the Invention
The present invention relates generally to devices for sampling chemical processes, and more particularly to a sampling device that readily permits collection of samples of varying size.
2. Description of the Related Art
It is typical in industrial processes to periodically sample the materials contained in, or conducted through, various parts of the process. The materials may be gases, liquids, slurries, or solutions, and the samples may be used for lab retention, product evaluation, or process analysis. Depending on the sampling requirement, the amount of sampled material needed can vary. The materials are often noxious or hazardous, and at the point of sampling may be under high pressure or at high temperatures. The design of a sampling device or technique should therefore address varying sample volume requirements and the prevention of inadvertent release of the sampled material from the process to protect the personnel taking the sample as well as other personnel, or the environment. It is also helpful for personnel taking a sample to be able to visually monitor the progress of the sampling to verify that the desired amount of sampled material is collected. Further, sampling devices are subject to wear or damage, and may be needed to be added or removed at various times to various points in the sampled process. It is therefore also desirable for sampling devices to be amenable to ready repair or replacement of parts, and to be easily installed and removed. A variety of sampling devices and techniques have been developed which do not satisfactorily address these needs.
A known liquid sampler is disclosed in U.S. Pat. No. 4,174,632 to Jansen ("Jansen '632"). The disclosed sampling device includes a branch line 3 fixed to a process line 1. A valve 4 is fixed to the branch line and includes a cap 6 surrounding an injection needle 9 and a desaeration needle 11. A sample flask 7 has a septum 8 in its opening. The interior profile of the cap is matched to the exterior profile of the sample flask. To take a sample from the process line, the sample flask is inserted into the cap so that the injection needle pierces the septum. The valve is opened, allowing the material in the process line to flow through the branch line, valve, and injection needle into the sample flask. When the desired amount of material is collected (monitored through a slot 10 formed in the side of the cap), the valve is closed, and the bottle withdrawn from the cap. The Jansen '632 device provides for only a single size of sample container. The entire sampler is suspended from the branch line, relying on the branch line's connection to the process line for support. The constituent parts of the sampler are not readily replaceable (for example, the injection and desaeration needles are fixed in the upper end of the cap). Further, the personnel taking the sample are potentially exposed to the sampled material, via the slot in the cap, if the sample flask ruptures.
Another known sampler is disclosed in U.S. Pat. No. 4,887,472 to Jansen ("Jansen '472"). The disclosed sampler includes a valve 1 (which communicates with the process to be sampled), a hood 2 coupled to the valve, a sleeve 3 mounted for reciprocal movement within the hood, and a bottle retainer 4 mounted for reciprocal movement about the exterior of the hood. Process needle 6 is mounted in the hood. A sample bottle 27 with septum 26 in its opening can be disposed within the bottle retainer 4, which includes a slit to enable the sample bottle to be viewed during filling. The Jansen '472 device also does not accommodate sample bottles of differing size, and similarly exposes the sampling personnel via the slit in the bottle retainer.
Soviet Union Patent Publication No. 549,706 discloses another sampler which appears to have a cap 14 mounted to a valve for reciprocal movement with respect to a fixed injection needle 11, and a bottle retainer 15 mountable to the cap to enclose a sample bottle 17. The bottle retainer 15 also appears to have a viewing slit 16. This sampler thus suffers from the same shortcomings as Jansen '472 and Jansen '632.